They're 6 pass shaves, on half of the face each, so I reckoned 3 was right. That's how my 1936 copy of "Accounting of Pogonotomy: Theory and Practice" tallies it, but it's outdated for sure. More recent editions are getting ridiculously expensive, so it's the best I've got. I've heard that in subsequent editions, the square root of the pass count is used for multi-pass, split-face shaves. So I guess my 6 pass = 2.449 rounded up to 2.5. Is that right?